1. Field of the Invention
This invention relates to scrubbing apparatus for purifying gas, particularly air, by intimate contact with an effective scrubbing liquid for a sufficiently extended period to purge the gas of pollutants, particularly styrene, and to purifying treatment of such a gas which is dynamically vibrated or agitated.
2. Problem
Air pollutants are of particulate character, of gaseous character, or both, and such pollutants result principally from industry or combustion. Industrial sources include ventilation products from local exhaust systems, such as from plastics manufacturing and processing plants, and process waste discharges, as well as from combustion. Air pollutants may be more or less odorous and/or pungent and/or noxious.
Known pollution control systems do not completely or effectively remove from air certain pollutants, such as those arising from paint booths, plastics fabricators, particularly those using styrene, and some petroleum processes.
Emissions from sewage and sludge treatment, restaurants, renderers, brewers and distillers, fish reduction and processing plants, pulp and paper mills, fertilizer processors and manufacturers, poultry and poultry processing operations, coffee roasting, garbage and garbage incineration, paint booths, internal combustion exhaust, plastics industries such as those which use styrene, petroleum processes, smelting and mining operations, swine, and other domestic stock and fowl raising, food processing operations, various chemical operations and operations such as printing where odoriferous materials are employed are amenable to treatment, at least to some extent, by the present invention.
3. Prior Art
The objective of prior air-cleaning processes has been to remove particulate matter and/or noxious gases and pungency. To remove particulate material, cyclone separators, bag filters and electrostatic precipitators have been used. In wet scrubbers, water is sprayed in atomized condition over a geometric shape or packed bed to remove water-soluble gases.
A typical cyclonic spray scrubber is shown in Figure 2 and a typical venturi scrubber is shown in Figure 3 on page 241 of Volume 1 of the McGraw-Hill Encyclopedia of Science and Technology, 1971 edition. A cyclone dust separator, a cloth collector and an additional view of a cyclonic liquid scrubber are shown on pages 333 and 334 of Volume 4 of the same publication.
In column 2 on page 47 of Volume 6 of the same encyclopedia it is stated that recovery of solute gases is generally achieved by contacting the gas streams with a liquid that offers specific or selective solubility for the solute gas to be recovered. By such procedure mercaptans can be removed from natural gas, or carbon monoxide can be recovered from process streams in petrochemical synthesis. Fluorides can be recovered from emissions from fertilizer and aluminum manufacture and sulfur dioxide can be recovered from metallurgical operations. Figure 1 on page 48 shows a diagram of a packed tower for gas absorption, Figure 2 shows a wet cyclone peripheral spray tower and Figure 3 on page 49 shows a plate tower or impingement baffle scrubber. Page 49 states that the packed tower is used most extensively in absorption operations because of its inherent differential mechanism and lower power consumption.
Thus various procedures have been used to purify air with greater or less success but conventional procedures have been unable to remove certain pollutants, such as styrene, from air. Also, air-filtering processes generally have required the expenditure of considerable power, or have utilized expensive equipment and/or materials, or have been of limited capacity, or have employed frequent and expensive reconditioning of sorption materials.